Maura's French Onion Soup

This crockpot version is elegant, but inexpensive and very easy to put together -- my husband loves it! I usually serve mine with a salad & freshly-baked loaf of bread. Lots of other French onion soup recipes seem to call for an extreme amount of butter, but I've found that 1 or 2 tablespoons, along with some well-browned onions, will yield a lovely rich flavor.